Device for covering openings in enclosed machines



Fgb. 28, 1950 v, HOLMGREN 2,499,190

DEVICE FOR COVERING OPENINGS IN ENCLOSED MACHINES Filed April 12, 1947 Fig.1.

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Ihvehtom Viking R Hoh'ngren, by W His Attorney.

- hole cover 8.

Patented Feb. 28, 195D DEVICE FOR COVERING OPENINGS IN ENCLOSED MACHINES Viking R. Holmgren, Lynn, Mass., assignor to General Electric Company, a corporation of New York Application April 12, 1947, Serial No. 741,113

Claims. (Cl. 171252) *My invention relates to a device used as a cover for an opening provided in an otherwise totally enclosed machine.

It is generally found that in the construction oflarge enclosed machines, such as those adapted to be used as large high speed turboelectric generators, one or more holes must be provided for functional purposes such as to provide a lift hole or to provide an opening to facilitate re-. pairs and adjustments. conventionally such a hole is covered by a blank cover plate, but such acovering is generally found expensive and unsightly and serves no useful purpose other than to cover the hole itself. In addition, removing such a'blank cover plate, in order .to make a visual inspection of the interior of the machine, is a time consuming process attended with the possibility of allowing the admission of dirt laden air'to the interior of the machine. It is, therefore, advantageous to have such large machines provided with a transparent inspection window so that at periodic intervals a quick inspection may be made to look for possible trouble in such form as water leakage, dirt accumulation an the like.

conventionally, such large machines are apt to have destructive pressures built-in therein, such as those caused by the introduction of high pressure steam to extinguish fires. Some means, such as a valve, must be provided for the relic of such pressures.

i It is an object of my invention to eliminate needless and expensive multiplicity of elements by combining in one device a cover, an inspection window, and a pressure relieving means. iaBroadly, the means employed in the embodiment herein illustrated and described comprises a lift hole cover for a turboge'nerator housing, said cover including a transparent window for inspection purposes, and said cover being so mounted relative to the mainhousing that it automatically serves as a pressure relief device whenever the need for such relief arises.

Other aspects of the invention will appear from consideration of the following description taken in connection with the accompanying drawing. In the drawing, Fig. 1 is a side elevational view of an enclosed top cooled tunbogenerator suitably embodying my invention and including the identical lift hole cover assemblies 8 and 9. Fig. 2

is a view taken on the line 2-2 of Fig. 1, and showing, in greater detail, the assembly of lift i In Fig. '1, I have shown a large top cooled electrical generator adapted to be driven by a steam turbine (not shown) through the rotatable shaft I of the generator. The generator is covered by a main housing 2 to which is attached, at the ass opposite the drive'end, the assembly of collector housing 3, exciter housing 4, and end bear- 2 ing housing 5; Housing 2 is provided with a. removable cover plate 6 behind which is located a top mounted cooler used in a conventional manner to cool ventilating medium circulated within the machine. A high pressure steam pipe I is used in conjunction with a thermostatic regulating device (not shown) to admit steam under pressure to the generator in case of a fire there- Four identical lift hole covers are provided, two on each side of generator housing 2, the two located on the side of the housing viewed in Fig. 1 being shown at 8 and 9'.

I have shown in Fig. 2 the assembly of lift hole cover 8 which, when fastened in place by a plurality of bolts I0, suitably encloses lift hole II inhousing 2. Lift hole II is one of four lift holes which, when the lift hole covers are removed, are adapted to receive hoisting means, such as hooks or slings, for lifting the entire machine, and for this purpose heavy structural support members, such as that shown at I2, are provided. These members bear the weight of the machine when it is being lifted, presume ably extending to the base or framework of the machine which is not shown.

Bolts I0 threadedly engage bolt holes I3 which extend through housing 2 to'hold the cover assembly 8 in place therein and optionally extend into support member I2 as well.

Lift hole cover assembly 8 includes an outer ring I4 provided with an annular recess adapted to receive an inner ring I5. Rings I4 and I5 are separated by a back gasket I6 and an edge gasket [6a. Said gaskets are fastened to only one of said members so that inner ring I5 may move axially outward away from outer ring I4.

A transparent window I! is provided at the center of the assembly and is held in place against the back side of inner ring I5 by a back ring IS, a plurality of flat headed machine screws, one of which is shown at I9, threadedly engaging said back ring to hold these members together.

- I prefer making the window-of a flexible transparent material for example, a transparent synthetic plastic, such as methyl methacrylate, since such material may be made structurally stronger and less subject to vibrational fatigue than ordinary window glass.

Screw I9 not only holds members I5 and I8 in contact with window I1 but said screw projects through the back "of back ring I8 and is holed to engage one-end of a'spring' 20, the other end of which engages a holed end of a stud 2| which, bymean's of a nut 22, is mounted on a back arm 23 Which-is solidly attached toouter ring I4. A guide pin ."24 solidly attached to back ringFIS and slidable through a hole in arm 23, is also provided. The construction; is:.;identical at-the back of each of the four machine screws 19 providedfor each: cover and the construction is identical for each of the four lift holecovers enclosed machine provided with lift holes and a device adapted to cover ione' of said lift holes, said device comprising an outer frame adapted to be secured to the outside of said machine to be manually removable from the outside thereof,

an inner frame resiliently secured to said outer frame by spring means arranged to bias said inner frame inwardly against said outer frame,

1 and a transparent window located within said is provided which allows visual inspection at any time without removing the cover.

The construction of the cover is such that under normal conditions it hermetically seals the lift hole; springs such as 20 exerting a con!- stant pressureto seal the window frame ring at the gasketing. Yet the construction is such asto provide the required pressure relief feature sincean excessive pressure within the housing, such as" that caused in the event of fire by the admission of high pressure steam through pipe, willovercome the restraining action of the springs and force the assembly of rings I5 and i8 and window I! axially outward to allow-the pressure to escape;

- The tension exerted by each spring 20 is manually adjustable, being controlled by'screw-- ing nut 22 in one-direction or the other and thereby determining the pressure at which the window will open. When the window has opened and excessive pressure dissipated, it will automatically reseal due tothe action of 'the springs and of the guide pins such as 24 which guide the movable part of the cover assembly so as to keep it always in proper diametrical relationship with outer ring l4.

There isthus provided a device of the character described which not only improves-the appear EHCG'Of the generator, and allows for rapid functional use of the hole to be covered, but which affords" means for quickly inspectingthe interior of" the machine; affords means for relieving destructive pressures within the housing of the machine and hermetically seals'the opening duringnormal operation, thus meeting the objects of the invention as hereinabove set forth.

- While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur' to thoseskilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and Iiintend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United-i- States I is:

1. A device adapted to cover a lift holein the housingof anenclosed turboelectric generator, said device comprising a cover for said hole; including an outer ring'provided with a plurality of bolt holes and bolts attaching saidringto said housing, an inner ring, said outer ring being adapted to receive said inner ring; tension spring means attaching said inner. ring .to said outer ring, a window'of. transparentmaterial, means including" a backup" ring for mounting said 'windowon said inner: ring; means including a threaded connection" for' varying the tension of said. tension spring means, andmeans including guide pins forassuringr proper. diametrical re lationship: between saidinnerring and said cuter ring.- I

-' 2. Thacombinatiou ofxasubstantiallytotally inner frame, whereby there is provided a combination inspection window and pressure relief means covering said lift hole.

3. The combination of a substantially totally enclosed dynamoelectric machine provided with lift holes on opposite sides thereof, and a plurality of similar devices each'adapted. to. cover one: of said lift holes, each of said devices come prising an outer frame adapted to' be bolted. ta theoutside of said dynamoelectric machine, an inner frame concentric with said outer. frame and arranged to be resiliently held against the outside thereof by a plurality of sprin members;

and a: transparent window located withinsaid inner frame.

4. An encased dynamoelectric' machine having: a plurality of lift holes in the casing thereof and having a steam connection thereto adapted to admit steam under pressure to extinguish a fire in said machine, With'means'for closing said: lift holes including a plurality of devices each havj ing an outer frame adapted to be bolted. to said casing around one of said lift holes and each having a transparent inspection window located within said outer. frame and resiliently secured against the outside thereof by. inwardly acting springs to provide for the emergency relief. of

excessive pressure within said casing when caused by the admission of steam through said steam connection, and manually adjustable means for selectively adjusting said springs to cause s'aid transparent window to close against said outer frame at a predetermined safe operating pressure within. said casing; I

5. An electric machine housing provided'with alift hole and a'device adapted to cover said lift hole, said device including. a window of. transparent plastic material, a mounting ring surrounding and secured to saidwindow, anouter ring adapted to surround and seat saidmounting ring and adapted to be demountablyattached to the outside of said housingspring' members arranged to draw said window mounting ring. inwardly against said. outer frame to seal said hole; and means for manuallyadjustingtheten sion of said springs to allow said window mounting' ring "to move outwardlywith respectto; said outer ring and saidhousing uponthe occurrence of a predetermined maximum allowable pressure within said housing;

VIKING- R. .HOIMGREN.

REFERENCES CITED The following references are-of record in the file of this patent:

UNITED STATES PATENTS eessz: Switzerland. "ea-1,1914 

